What have you developed before so that people can pick the right tutorials for you? What sort of experience have you had? Most people here will tell you that before you start something complicated like a fighting game you need to start small.

Collision Detection and proper gameplay in 2d fighting games are pretty difficult to do e.g.(street fighter 2, kof, guilty gear, etc). One engine on the PC called MUGEN did this pretty well.

MUGEN was not written in java and its source was not released, however there have been plenty clones of it over the years whose source code has been released, doing a few searches on it may help you with some tutorials or code.

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